Self-lubricating stuffing box



6, 1968 M. A. REMKE ETAL 3,395,923

SELF-LUBRICAT ING STUFFING BOX Filed July 9, 1965 2 Sheets-Sheet l 47 72 3 I 48 49 -LF 52 f 39 INVENTORS M. A. REMKE BY F. e. L YTE A TTORNEYSAug. 6, 1968 M. A. REMKE ETAL SELF-LUBRICATING STUFFING BOX Filed July9, 1965 2 Sheets-Sheet 2 FIG. 4

FIG. .5

IN VEN TORS M. A REMKE BY F. c. LYTE A T TORNEV Unitd States Patent3,395,923 SELF-LUBRICATING STUFFING BOX Marvin A. Remlre and Frank G.Lyte, Bartlesville, Okla,

assignors to Phillips Petroleum Company, a corporation of Delaware FiledJuly 9, 1965, Ser. No. 470,835 2 Claims. (Cl. 277-59) ABSTRACT OF THEDISCLOSURE In an oil well tubing head having a chamber connected to thetubing, with a stufiing box at the top of the chamber, a polished rodreciprocating through said box and chamber, and an oil outlet conduit tosaid chamber, the improvement comprising an oil-retaining cup slidablymounted on said rod and secured in said chamber, with said oil outletconduit connected to said chamber at a point at least as high as the topof said cup, whereby when oil passes from said tubing out said conduitit will also fill said cup which will retain said oil in contact withsaid rod for a substantial period of time. A further improvement is ahelical spring around the rod between the stufiing box packing andpacking between the cup and rod to separate the two packings and urgethem into packing contact with the rod.

This invention relates to a self-lubricating stufiing box. In one aspectit relates to such a stufiing box for an oil well tubing in which thereis an oil reservoir positioned to receive and retain a small portion ofthe oil being pumped in such a position that the polished rod duringpumping is reciprocated through the oil in said reservoir so as tomaintain an oil layer on the surface of said polished rod and obviatepulling a dry rod through the packing in the stufiing box and therebydestroying said packing.

In the prior art, difliculty has been experienced due to the surface ofthe polished rod drying out between the times that oil is being producedfrom the well and pumped to the surface through the tubing by areciprocating movement of said polished rod through the packing in saidstufiing box.

The dried-out polished rod will stick against the packing and soon tearthe same to pieces.

While attempts have been made in the prior art to lubricate suchstufiing boxes, such attempts are generally unsuccessful. This lack ofsuccess is due in part to the poor design of the lubricating means, andin part to the operator forgetting to actuate or renew the lubricatingmeans.

The present invention avoids these objectionable features of the priorart by maintaining a reservoir of oil obtained during pumping in aposition where the polished rod passes through the same so that thepolished rod remains wet with oil, or is immediately wetted with oilupon restarting the pump, so that it will not adhere to the packing andtear up the same. Means is provided to readily renew the body of oil insaid reservoir whenever oil is pumped.

One object of the present invention is to provide an improvedself-lubricating stufiing box. Other objects are to provide improvementsin the elements employed in such stufiing boxes.

Numerous other objects and advantages will be apparent to those skilledin the art upon reading the accompanying specification, claims anddrawings.

FIGURE 1 is an elevational view With parts broken away in cross sectionof a stufling box embodying the present invention.

FIGURE 2 is a cross-sectional view of the apparatus 3,395,923 PatentedAug. 6, 1968 "ice of FIGURE 1 taken along the line 22 looking in thedirection indicated.

FIGURE 3 is an elevational view with parts broken away in cross sectionof a second modification of the stufiing box.

FIGURE 4 is a similar elevational view with parts broken away in crosssection of a third species of the present invention.

FIGURE 5 is an elevational view with parts in cross section showing thepresent invention applied to the tubing of an oil well.

FIGURE 6 is an elevational view of one form of stufling box packingshown in FIGURE 4.

FIGURE 7 is an elevational view of a second form of stuffing box packingthat could be used in place of that shown in FIGURE 6.

In FIGURE 1 a tubing head 11 is shown containing a self-lubricatingstufling box for the top of an oil well tubing. The tubing head 11 isprovided with threads or other connecting means 12 adapted to beconnected to the tubing 13 (see FIGURE 5) of a pumping oil well throughwhich oil 14 is at least intermittently pumped by a pump (not shown)inside pumping housing 16 actuated be a reciprocating polished rod 17passing into said tubing 13 through said head 11. The head 11 has avertical conduit 18, 19, 21, 22, 23 and 24 passing said rod, a chamber26 forming a portion of said conduit, and a branch conduit 27 beingconnected to said chamber for the outlet of oil pumped into said chamberby said pump.

This improved self-lubricating structure comprises in combination anoil-retaining cup 28 mounted in said chamber 26 around said rod 17, alower packing 29 between the body of said cup 28 and said rod disposedto form an oil-retaining space 31 between said rod 17 and said cup 28above said packing 29, and a stufiing box having upper packing 32, 33and 34 disposed at the top of said chamber 26 and sealing between thebody 36 of said head and said rod 17 above said oil-retaining space 31and said branch conduit 27.

While not essential to the invention, it is preferred that in the cup 28around the rod 17 and between the lower packing and stuffin g box thereis disposed an upper packing follower 37, a lower packing follower 38and a helical compression spring 39 separating the two followers andurging them against their respective packing 32, 33, 34 and 29.

In FIGURE 1 the upper and lower packing comprises conical resilientpacking rings 29, 32, 33 and 34. While not necessary to the invention,it is also preferable in some instances to provide a resilientdust-wiping ring 41 retained in groove 42 of a stufling box follower 43preferably threaded at 44 into stufiing box head 36, which in turn isretained by nuts 46 and bolts 47 to the top of tubing head 11. While notessential, tubing head 11 is often provided with an outlet 48 of lesserdiameter than oil outlet 27 for the purpose of removing samples of gas,measuring pressure or the like. Cup 28 is provided with a plurality ofwindows 49 allowing free passage of oil between cup 28 and tubing headchamber 26. The bottom of cup 28 is supported on ring 23, which may besupported on radial fins 51 in the chamber 26. However, other suitablemeans of supporting the cup obviously may be employed.

During pumping, oil coming up passage 24 through chamber 26 to flow line27 overflows through windows 49 into cup 28, filling the same up to thelevel 52 of the bottom of windows 49. Later, when no oil is beingpumped, the reservoir of oil in 28 up to level 52 acts to keep thepolished surface of rod 17 wet with oil. Even if the oil dries out abovelevel 52, as soon as the rod 17 again is reciprocated some of the oilwill be carried on its surface up into the upper packing 41, 32, 33 and34 and, of course, into the lower packing 29 so that the packing willnot be destroyed by a dry rod 17.

FIGURE 2 is a cross section of FIGURE 1 and needs no furtherexplanation.

FIGURE 3 is a second embodiment of the present invention in which theupper packing 53 comprises loose packing material and a grease nipple 54in said stufiing box accessible from the outside of said tubing head 11is connected to supply grease to fill the space in said loose packing53. When not using the follower 43 and dust ring 41 of FIGURE 1, asimple follower or closure means 56 may be substituted at 44.

In FIGURE 3 the cup 57 is provided with an integral bottom 58, a lowerrubber packing washer 59 and a steel follower 61 below helicalcompression spring 62 which presses upwardly on upper follower 63provided with spring centering boss 64 against loose packing 53 retainedin cup 57 by threaded cover 66.

Although not essential, if desired a rubber O-ring 67 may be provided inan annular slot in the top of cover 66 to seal against head 36 toprevent the escape of fluid from chamber 26 through the central passagein 56.

Parts having the same number are the same as parts shown in FIGURE 1.

All the various packing members 41, 32, 33, 34, 29, 67, 59, 68, 69, 71and 72 may be made of oil-resistant synthetic rubber, such as Neoprene(trademark), and the same or other well known material can be used forgaskets 73. Hemp or polyolefin fiber can be used as packin 53.

In FIGURE 4, tubing head 11 has a cap 74 with an upper thread end 76into which a retaining ring 77 is threaded. Retaining ring 77 holds downthe top of cup 78 which has an open top closed by follower 79 which maybe provided with annular O-rings 71 and 72. Between spring 62 andfollower 79 is disposed a helical tube of resilient material 69, theelevation of which is shown in FIGURE 6. The inner surface of 69 may beprovided with an annular saw-tooth surface 81 to provide a series ofhorizontal serrations or annular ridges on its inner surface wiping onrod 17. As shown in FIG- URE 3, the lower packing may be a flat ring ofresilient material 59.

In FIGURE the stufiing box 11 of FIGURE 1 is shown applied to an oilwell generally designated as 82. The well comprises a well bore 83extending down through geological formations 84, 86, 87 and part of 88.Oil from oil bearing formation 87 passes through holes 89 in casing 91and rises by natural hydrostatic pressure to level 92. Casing 91 isprovided with a casing head 93 supporting a tubing support ring 94 inwhich tube 13 is secured. Stufling box 11 is secured in tubing 13.

A Samson post 96 supports a walking beam 97 which is actuated by apitrnan 98 to reciprocate polished :rod 17, which rod extends throughstufiing box 11 down through tubing 13 to a pump (not shown) in pumphousing 16. When reciprocated, pump 16 tries to pump oil 14 up tubing 13through stufling box 11 and out oil flow line 27. However, in many wellsthe oil level 92 is pumped down below the intake of pump housing 16,upon which rod 17 is liable to be wiped clean of oil and dry out.Pumping is discontinued. In the prior art, when pumping is renewed, dryrod 17 will tear up the packing. In the present invention, the cup 28,57 or 78 will retain a reservoir of oil up to level 52 at the bottom ofwindows 49, so that when pumping is renewed polished rod 17 is still wetwith oil or is made wet with oil on the first stroke of the pump,thereby lubricating the packing and preventing the rod from tearing upthe packing. It is therefore obvious that we have provided aselflubricating stufiing box for an oil well tubing as claimed below.

FIGURE 6 is an elevational view of the helical tubular rubber packing 69of FIGURE 4.

FIGURE 7 is an elevational view with a portion in cross section of anannular tubular rubber packing 68 which can be substituted for packing69 in FIGURE 4.

While certain specific embodiments of this invention have beenillustrated in the drawing and described in the specification in orderto explain the invention, it is obvious that the invention is notlimited thereto.

Having described our invention, we claim:

1. A polished rod stufiing box assembly comprising in combination:

a tubing head having a body adapted to be secured to an oil well tubing,said body having a first vertical passage therethrough, the bottom ofwhich passage is adapted to be connected in communication with saidtubing;

said first vertical passage being adapted to have a reciprocatingpolished rod passed therethrough in spaced relation therewith;

said body having a chamber forming a part of said first verticalpassage;

an oil-retaining cup secured to said body with the top,

the wall and the bottom of said cup in spaced relation to the wall ofsaid chamber inside said chamher, with a vertical second passage throughthe bottom of said cup adapted to have said polished rod passedtherethrough. in spaced relation to the wall of said cup;

first packing means secured in the bottom of said cup adapted torestrict the flow of oil between said cup and said rod and thereby toform a substantial oilretaining space between said rod and said cup fromabove said first packing to the top of said cup;

the top of said cup communicating with said chamber;

second packing means secured in said body adjacent the top of saidchamber adapted to restrict the How of oil between said body and saidrod; and

a conduit connected to said chamber at a point at least as high as thetop of said oil-retaining space in said cup for the outlet of oil fromsaid chamber;

whereby when oil passes from said tubing out through said conduit iswill also positively fill said oil-retaining space in said cup bygravity flow over the top of said cup, and then said cup will retainsaid oil in contact with said rod for a substantial period of time.

2. The combination of claim 1 in which in the cup around the rod andbetween the first and second packing means there is disposed a helicalcompression spring separating the two packing means and urging them intopacking contact with said rod.

References Cited UNITED STATES PATENTS 1,585,087 5/1926 Dcems 277-4 X1,594,935 8/1926 Force 277--S9 2,538,207 1/1951 MacArthur 27710O2,628,112 2/1953 Hebard 277-68 X 1,603,206 10/ 1926 Hull 277-62 X1,805,155 5/1931 Weeks 277-72 X 1,877,696 9/ 1932 Schellack et al 277-72X SAMUEL ROTHBERG, Primary Examiner.

